Apparatus for desiccation



oct. 12, 194s. o. BEBER 2,451,316

APPARATUS FOR DESICCATIN Filed Oct. 19. 1942 2 Sheets-Sheet 1 l i N Oct, 12, 1948. o. Bil-:BER

APPARATUS FOR DESICCATION 2 Sheets-Sheet 2 Filed Oct. 19. 1942 /ITTR/VEY Patented Oct. l2, 1948 UNITED STATES PATENT `OFFICE APPARATUS FOR DESICCATEON Otto Bieber, New York, N. Y.

Application October 19, 1942, Serial"462,520t

(Cl. :M -216) 2 Claims. 1

This invention relates to apparatus for dehydration andl in particular is directed to an improvement in the construction of ltunnel-type dehydrators.

Many forms of apparatus used for dehydration, particularly of foods and feeds, produce materials which are either incompletely dehydrated or are impaired in quality because the operators have y used excessive temperatures inv trying to drive the dehydration to the limit. When the degree of dehydrationv falls short of the optimum con'- scnant lwith quality of the product, the drying apparatus clearly is inefficient. When the dehydrationA has over-shot its mark andk produced a material of impairedquality, there is likewise a severe economic loss.

It is, therefore, an object of thisinvention to provide an apparatus which will produce a dehydrated material, particularly a food or feed ci high quality, containinga minimum of residual liquid.

Another object is to provide an apparatus which will operate effectively under severe loads and will require but little mechanical servicing.

Another object is to provide an apparatus which may` be readily adjusted for 4the* dehydration of a great Variety of materials, such'as,vfruits, vegetables, meat, iish, grain mashes and the like.

Another object is to provide an apparatus which may be constructed orv assembled from relatively inexpensive structural materials and With a minimum of engineering supervision.

Another object is to provide an apparatus having means for easily adjusting or controlling the degree of dehydration at various stages in the operation soI as to yield a product of optimum value.

Another object is to provide anv apparatus capable of handling small loads or large loads,

thereby oiering thedehydrator greater nexibility L in.y che use of a single installation.

The essence of the invention which renders the foregoing objects possible of accomplishment resides in providingy means for:

(a) Conveying the material to be dehydrated f through atunnel.

(D) Generating currents of dehydrating vapors a plurality of positions in the tunnel.

(c) Controlling the temperatures at a plurality of positionsin thetunnel.

(d) Controlling they velocity and volume of the exhausts at a plurality `of positions in the tunnel- (c) Exhausting a substantial portion of the vaporized moistureyielded by the material undergoing del'iilfdratifmy close tothe area or vicinity of its release, at a plurality of posi-tions inthe tunneL and immediately thereafter permitting the unexhausted portionV to expand.

('f) Raking and turning the material being processed at a plurality off positions in the tunnel so as to effect greater uniformity in the rate of dehydration and more thorough elimination of moisture from the finished product.

Further` objects and a fuller understanding oi the invention will: be gathered upon reading the following detailed description. in: connection. with the accompanying drawingsherein:

Figure l is a View, partly in outline and partly in section, diagrammatically illustrating. the ap paratus constructed in accordance-With the present invention.

Figure 2 is an enlarged View in section` taken on the line 2-2 of Figure 1 and looking in the direction of thearrows.

Figure 3 is an enlarged view in. sectiontaken onthe line 3--3 of Figure 1 diagrammatically illustrating the raking devices.

Figure 4 is an enlarged viewin section diagram-l matically illustrating the'lowermost section of they apparatus illustrated in Figure 1.

Figure 5 is aV partial View in section showing the structural arrangement of one ot the roller `hearings supporting they conveyor belt.

Referring again tothe drawings, the dehydration tunnel is built up around a. frame consisting of the-two parallel U beams H and pairs of ang-le irons i2 connected Witheach other toform the frame. The width of the frame may be varied depending upon the-length of tie rodsvvvhichconnect the tWo U beams Il to eachother andsimilarly connect the angle irons i2 with each other, The frame is supported on a series ofstanchions of increasing height. This arrangement. on the stan-chiens isV used when the length of the apparatus is greater'than the floor space, other-` iwise it may be construed parallel` with the floor.

On this frame a tunnel` roof isV formed by means of a series of' connected insulated sheet metal coverings |61, l'iand t8-, This roof has the outline of a tilted savvtooth roof. The sections of the sheet metal ma-y queV bolted, spot-Welded or otherwise assembled to form the tunnel roof by means customarily used in such structural'- art. In like manner they are also attached to the frame.

The-floor ofthe tunne'lis-formed by means of a series ofmetal trays 2li' resting `en-guidesllwhich are fastened tothe base-'of the frame, lower angle irons I2, in any convenient manner customarily followed in assembling such structural materials.

These trays also are used -to adjust the air intake of the apparatus. By 'opening these sections of the tunnel iloor to a desired position the operator can readily adjust the volume of intaken Iair to suit 'the needs of any particular operation at any desired point. The walls of the Itunnel are formed by means of a series yof enclosing removable sheet metal sections 28 which are attached to the frame. They Iare provided with handles 29 and are attached to the frame by means of conventional fastening devices permitting easy removal whenever it becomes necessary to obtain access tothe interior of the tunnel. f

Each of the Itunnel roof sections I6, H and I8 are connected .to a mast-er exhaust pipe or ducts 22 by means of individual ilues or ducts 23, 2li and 25.

These flues decrease in diameter at their advancing positions inthe apparatus. This decrease is an important feature'. Since the moisture content -of the exhaust decreases in the advancing pos-itions of the apparatus, it is important to decrease 'the volume of the exhaust in order to conserve as much as possible oi the hot dry air so that it may be reutilized. The exhaust system is actuated by an exhaust fan 26.

In order to utilize the dry hot air which arrives at the exit of the tunnel, a pipe 21 provides the means for returning this valuable sourcefof energy .to the entrance.

The entire tunnel is tightly constructed and insulated, Wherever possible, in order to minimise heat radiation losses.

Within the tunnel there is a conveyor system comprising an endless belt 3B mounted on a driving pulley 3i and a take-up pulley 32. The belt rides over a series of rollers 33 which rotate on roller bearings 35 about an axle 35 which may be attached to the frame in any convenient fashion that will Iallow for their leasy rem-oval and reinstallation whenever it is necessary to do so. The conveyor system is actuated by a motor 35 connected to a speed reducer 31 which is connected with the driving pulley 3l. It will be understood that the conveyor system may be driven by Vany other appropriate means which will produce the requisite velocity of .the belt.

'Each of the sides of the tunnel roof sections is provided with removable windows 38 which also function as manhole covers. In each of the foregoing sections there is :a fan 4B actuated by its 'own' variable speed motor 4|, d2 and t3 through a driving belt 44. The fans may also be directly driven bythe motor.

The apparatus is heated by means of a series of gas burners i5 connected to a gas supply line iii. Each burner is provided with a cock for separately regulating and controlling the temperature in the tunnel sections heated by .the burners. To facilitate lighting of the burners the side walls are provided with self Vclosing shutters 4l. Y

The apparatus is provided with a series of baflles located under the burners l5 in order to prevent undue heating of the belt conveyor. Another series of -baiiles 5I are positioned above the burners to prevent the direct flame from impingingon the belt and the materials `carried Y thereby. E i' Y Y The Vbelt conveyor is constructed Vof an open mesh screening material, which facilitates the dehydration process. TheY meshing is large enough to expose as much as possibleloi the ma- V terialbeing processed to the action of Ythe hot air. Each of the dehydration sections formed by theV 4 tunnel roofing section-s I6, I1 and |8 is provided with a movable baille 52. These baiiles mounted on rods 53 are actuated by means of external handles 54 which can be securely fastened so as to keep the baiile in any selected position. The bailes are mounted -on rods in conventional fashion.

The tunnel is also provided with means for illumination such as incandescent bulbs 55. In place of these bulbs, the apparatus can be provided with ultra violet lamps, e. g., of the Ymercury vapor type. The ultra violet rays will be valuable `for their sterilizing properties or activating characteristics, e. g., vitamin formation from precursors.

'Ihe apparatus is provided with a plurality of rakes having curved broad teeth angularly disposed in alternating directions. These teeth 56 and 5l', mounted on rods 58 respectively, play an important role in the operation of the apparatus.

i As the material being dehydrated is conveyed on the belt through .the tunnel, it is upturned and tossed from side to side by these raking means thereby keeping the mass constantly vbroken up and more thoroughly vand evenly dehydrated. Since the belt is of open work structure the drying gases pass through the material undergoing dehydration. Y Y

The nues 23, 2li and 25 are each provided with butterfly dampers 69. Y

Each of the dehydration sections is provided With a baffle such as the one illustrated in Figure 4, numeral 6I. These bailles increase in size at their advancing positions in the apparatus. 1The increase in size is important because of the need to lessen the effect of direct blast of the immediately superior fan on the material being dehydrated. As the dehydration progresses the material becomes lighter and would, therefore, be more readily-blownoff the belt if these baiiles were not increased in size. K

The discharge end of the tunnel is provided with an enclosure of insulated sheet metal, or equally effective material. which covers the driving Ypulley 3|. This enclosure is connected with` a hopper 65 to receive the dehydrated material as it is discharged from the beltl conveyor. hopper empties into a receptacle 66.

In order to carry out a dehydration with this apparatus, the conveyor belt`30'is put in motion; the burners l5 are lit; and all fans arestarted. Then the material to be processed is fed into the apparatus and evenly distributed across the breadth of the belt 3U. The temperatures and moisture content of the air in the tunnel is observed or recorded by means of appropriate instrumentation. The readings ,are taken from conditions prevailing midway between the fans 40 and baffle 52. In order to maintain, at these positions, predetermined conditions of temperature and moisture, depending upon the character Y of the product being processed, theV gas burners e5 are adjusted and the tunnel air intake regu-- lated by positioning of the trays 20. Further adjustments are made by baiiling the air blast from the Vfans 4! through movement of the baffles 52 and regulating the volume of the-exhausts in ues y23, 24V and 25 through movement of dampers 60.

YIt will be observed that by means of this apquantity of the moisture released fromV the material being dehydrated almost immediately after the processing begins and that thisrexhausting is accomplished at several stages in the operation. In this way it is possible to achieve a muchA more rapid and effective dehydration than has hereto- The fore ever been done in this art. Furthermore the provision of means for allowing the unexhausted vapors to expand as they enter the next position enables the operator to achieve surprising results in the dehydration at each such stage. These repeated expansions of the unexhausted vapors enables the operator effectively to carry out a dehydration at much lower temperatures than has heretofore been possible in this art, and nevertheless preserve the flavor and vitamin content of the materials.

It is also to be observed that in place of the gas burners it is possible to use any other devices or means which will develop currents of hot air t0 effect the dehydration.

It will also be observed that the movable baille permits the operator further to adjust the temperature in tunnel section I6 either at the initiation of the heating of the tunnel or at any time during the beginning or continuance of the dehydration operation.

Having thus described the invention, I claim:

1. In a drying apparatus the combination of a tunnel having a substantially saw-toothed roof; an open work conveyor belt adjacent to the base line of the tunnel roof but spaced therefrom to form a plurality of throated sections thereby providing a series of connected narrow passageways to permit the passage of the material being dried and the gases above said material from one section to the next section; means at a plurality of positions in the tunnel below the conveyor belt for supplying hot drying gases to said sections;

an exhaust duct situated adjacent the throat of one of the aforesaid sections; a fan within one of said throated sections between said roof and said conveyor belt for circulating said drying gases in contact with the material carried on the conveyor; and adjustable ports in the tunnel beneath the conveyor belt to permit the entrance of air at atmospheric temperature into the tunnel.

2. In a drying apparatus the combination of: a tunnel having a substantially saw-toothed roof; an open work conveyor belt adjacent to the base line of the tunnel roof but spaced therefrom to form a plurality of throated sections thereby providing a series of connected narrow passageways to permit the passage of the material being dried and the gases above said material from one section to the next section; means at a plurality of positions in the tunnel below the conveyor belt for supplying hot drying gases to said sectionsi an exhaust duct situated adjacent the throat of one of the aforesaid sections; a fan within one of said throated sections between said roof and said conveyor belt for circulating said drying gases in Contact with the material carried on the conveyor; and an adjustable baffle within said last mentioned section for regulating the aforesaid circulation of the drying gases in contact with the material carried on the conveyor.

OTTO BIEBER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 585,759 Hysore July 6, 1897 931,873 Hough et al Aug.24, 1909 1,034,112 Hopkins July 30, 1912 1,049,930 Skinner Jan. 7, 1913 1,266,983 Parker May 21, 1918 1,375,080 Chappell Apr. 19, 1921 1,385,365 Dreyfoos July 26, 1921 1,460,519 Wadsworth July 3, 1923 1,567,031 Buensod Dec. 29, 1925 1,572,326 Straight Feb. 9, 1926 1,670,991 Schilde May 22, 1928 1,750,839 Furbush Mar. 18, 1930 1,751,472 Criqui Mar. 25, 1930 1,788,099 Fulmer Jan. 6, 1931 1,966,405 Galson et al July 10, 1934 2,149,813 Lindstron Mar. 7, 1939 2,270,111 Daley Jan. 13, 1942 2,272,383 Poor, 2d, et al Feb. 10, 1942 2,280,704 Hurxthal Apr. 21, 1942 2,326,115 Arthur Aug. 10, 1943 2,359,199 Burnett Sept. 26, 1944 FOREIGN PATENTS Number Country Date 12,389 Great Britain 1901 15,140 Great Britain 1899 61,385 Sweden Aug. 17, 1926 81,051 Germany May 9, 1895 224,708 Germany (Marr) July 29, 1910 236,936 Great Britain Oct. 22, 1925 336,009 Great Britain Oct. 9, 1930 535,718 Germany Oct. 14, 1931 

